<?php
namespace Util;
class Character{
	/**
	 * 获取6位随机数字
	 * @param int $len
	 * @param string $format
	 * @return string
	 */
	public static function randStr($len=6,$format='NUMBER') {
	    switch($format) {
	        case 'ALL':
	            $chars='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-@-~'; break;
	        case 'CHAR':
	            $chars='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-@-~'; break;
	        case 'NUMBER':
	            $chars='0123456789'; break;
	        default :
	            $chars='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-@-~';
	            break;
	    }
	    mt_srand((double)microtime()*1000000*getmypid());
	    $password="";
	    while(strlen($password)<$len)
	        $password.=substr($chars,(mt_rand()%strlen($chars)),1);
	    return $password;
	}
}